The present invention relates to an electronic device having multiple antennas and, more particularly to an electronic device for reducing interference between the multiple antennas by engaging a decoupling electronic circuit for the electronic device operable in a wireless communication system.
A communication system is operable to communicate information between a transmitting station, also referred to as a calling party, and a receiving station, also referred to as a receiving or called party, by way of a communication network. Operation of a wireless communication system transfers information between the transmitting and receiving stations via one or more base stations. These transmitting and receiving stations are also known as wireless communication devices, cell phones or mobile phones, Personal Digital Assistants (PDA""s), or portable computers. As the capability and sophistication of the wireless communication system has increased, the demand for mobile communication devices having at least two antennas has proliferated. Previous mobile communication devices having multiple antennas utilize an electrical or mechanical switch to provide an RF signal to one of the multiple antennas, thereby providing an active antenna. However, the non-active antennas on the mobile communication device can degrade the performance of the active antenna. Among the concerns for locating multiple antennas within a limited space of a mobile communication device is the interference, or coupling between the antennas. Typical solutions include greater separation between the antennas to minimize the interference. Consequently, the relatively small dimensions of the mobile communication device restricts the available separation of the antennas. It would be useful to provide decoupling, also called detuning, or changing resonant frequency, of multiple antennas of a mobile communication device, while achieving sufficient gain and impedance matching of the antennas.
The present invention encompasses an electronic device having multiple antennas detuned to minimize interference and operable in a wireless communication system, where the electronic device can comprise a mobile station, a personal digital assistant (PDA) or a portable computer. The apparatus of the present invention comprises an internal antenna, an exterior antenna, and a detuning circuit to alter resonant frequency of the inactive antenna and thereby minimize interference between the antennas. Detuning circuitry may cooperate with either the interior antenna or the exterior antenna to minimize interference during operation of the electronic device. In addition, activation of the detuning circuit can be by achieved by positioning the exterior antenna to cooperate with the detuning circuit.
A more complete appreciation of all the advantages and scope of the present invention can be obtained from the accompanying drawings, the following detailed description of the invention and the appended claims.